This application claims the priority of German Patent Document 199 63 030.5, filed in Germany, Dec. 24, 1999, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a combined disk and drum brake with an internally ventilated brake disk of the type referred to in German Patent Application No. 199 08 914.0.
German Patent Document DE 38 24917 A1 discloses a brake with a protruding sheet metal plate for guiding splashing water away from the brake drum.
A combined disk and drum brake with an internally ventilated brake disk is described with respect to the construction referred to above. For avoiding a penetration of water onto the contact surface of the inside shoe brake in a friction ring of the brake disk, the brake disk has a ring duct with two opposed ring grooves. An inclined water guiding metal plate of an exterior shield projects into the ring duct and, on the one hand, collects the splashing water in a water inlet position and releases the collected splashing water in a water outlet position.
It is an object of the invention to absolutely avoid, in the case of an internally ventilated brake disk with an inside shoe brake arranged in the brake drum, a penetration of splashing water onto the contact surface of the inside shoe brake and to provide a targeted water drainage by means of a ring groove which is easy to produce and which forms a surrounding duct in the brake disk.
According to the invention, this object is achieved by providing a combined disk and drum brake with an internally ventilated brake disk, having two friction rings, having a surrounding water guiding metal plate bent away from a shielding metal plate, and having an inside shoe brake arranged in a brake drum, in the interior friction ring, a ring groove being provided which, in its base, has passage openings to air guiding ducts between the friction rings, and a narrowed groove opening being provided which is situated opposite the base, which narrowed groove opening is adjoined by opposed ring surfaces within the ring groove, and the bent-away water guiding metal plate projecting into the ring groove and between the ring surfaces, and being set at an angle with respect to the ring surface such that, in an approximately vertical water entry position, the guiding plate is set at an acute angle with respect to the ring groove base and simultaneously forms a draining slope in an approximately vertical water outlet position of the guiding metal plate, wherein the ring surfaces in each case laterally bound the ring groove and form a water draining and a water collecting surface which are both arranged to be inclined with respect to the shielding metal plate at an angle (xcex1, xcex2) and to be jointly narrowing the exterior ring groove opening.
Principal advantages achieved by the invention are that the ring groove in a friction ring of the brake disk with one water draining surface and one water collecting surface respectively can be produced in a simple manner. These surfaces, which bound the ring groove laterally or on the top and on the bottom, have different flat constructions and are arranged to diagonally extend toward the exterior groove opening such that a narrowed exterior groove opening is obtained.
So that the splashing water or water entering the brake disk can, without distinct ring ducts, be nevertheless collected in the lateral walls of the ring groove and be rapidly discharged to the outside, one upper lateral surface of the ring groovexe2x80x94viewed in the water entry positionxe2x80x94is slightly curved and the lower opposite lateral surface is provided with an indentation with respect to the adjoining duct wall of the air guiding duct.
On the whole, the indentation in the lateral surface is situated below the level of the adjoining duct wall of the air guiding duct and is arranged to be inclined with respect to this duct wall and has a rounded end area.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.